This invention relates generally to fittings, and more specifically to methods and apparatus for coupling a conduit to a fitting.
At least some known conduit fitting assemblies include a collar coupled to an end fitting. The end of the conduit end is received within a portion of the collar, and a portion of the end fitting is received within the conduit end. More specifically, the portion of the collar that includes the conduit end is then compressed radially inwardly such that the conduit end is compressed between the end fitting and the collar. When compressed, friction created between the collar and an outer surface of the conduit end, and friction created between an inner surface of the conduit end and the end fitting retains the conduit end within the collar.
At least some known collars are threadably coupled to the conduit end fitting, while other known collars include an offset that mates with a reduced diameter portion of the end fitting when compressed to secure the collar to the end fitting. However, such conduit fitting assemblies may require an extended length to ensure a secure connection is created between the collar and the conduit end fitting. Accordingly, the cost and overall weight of the conduit fitting assembly may be increased. Furthermore, known end fitting assemblies may not include a generally uniform end fitting nipple portion outer diameter, which may increase difficulty of inserting the fitting nipple portion within the conduit end.
Other known conduit end fitting assemblies include a mandrel that is inserted within a passageway defined in the end fitting to support the end fitting and to prevent partial, or complete, collapse of the passageway. Typically, a mandrel is a rigid metallic tool that is received within the end fitting. However, for complex conduit geometries, a mandrel may be an eutectic compound that is inserted within the end fitting. Mandrels may increase the labor and tooling required to produce such fitting assemblies. In addition, when the mandrel is a eutectic compound, the eutectic compound may contaminate fluid flowing through the fitting assembly.